What are the complications associated with total knee dislocation?
Popliteal artery injury (tear, intimal tera & thrombosis)
Nerve injury – common peroneal nerve
Tear of all four ligaments
Why must regular foot examinations be undertaken following a total knee dislocation?
Intimal tears may occur causing thrombosis
Vascular status of foot must be monitored
What is the treatment for total knee dislocation?
External fixation for stabilisation
Mulitple ligament reconstruction
What can cause an osteochondral injury?
Impaction or shear of the articular surfaces or due to a direct blow
What investigations should be done for suspected osteochondral injury?
How should acute injuries with large oestochondral fragments and substantial amounts of bone be managed?
Fixation with pins
What management option is availiable If a defect due to osteochondral injury has bare bone at its base?
Microfracture - holes can be drilled into the defect to induce bleeding and encourage formation of fibrocartilidge, scar type hyaline cartilidge, to repair the defect
What are the components of the extensor mechanism of the knee?
What are some predisposing factors to development of extensor mechanism rupture?
History of tendonitis
Chronic steroid use or abuse (body builders)
Chronic renal failure
What kind of injuries can cause ruputre of the patellar tendon or the quadriceps tendon?
Rapid contractile force which can occur after lifting a heavy weight, after a fall or spontaneously in a severely degenerate tendon
Which patients are more likely to have patellar or quadriceps tendon rupture?
Younger - patellar tendon (<40)
Older - quadriceps tendon (>40)
Why should steroid injections for tendonitis of extensor mechanism be avoided?
High predisposition to tendon rupture
What signs might extensor mechanism rupture show on examination?
Difficulty with straight leg raise test
Palpable gap in extensor mechanism
How might extensor mechanism rupture show on Xray?
Low lying patella (quadriceps tendon rupture)
High lying patella (patellar tendon rupture)
What is patellofemoral dysfunction?
It describes disorders of the patellofemoral articulation resulting in anterior knee pain
What are some of the symptoms of patellofemoral dysfuncton?
Anterior knee pain - worse going downhill
'Clicking' or grinding sensation at front of knee
Stiffness after prologned sitting causing psuedolocking
What are some predisposing factors to patellofemoral dysfunction?
Femoral neck anteversion
What can cause the anterior knee pain in patellofemoral dysfunction?
The pull of the quadriceps muscle tends to pull the patella in a slight lateral direction: in some people, excessive lateral force produces anterior knee pain and the lateral facet of the patella is compressed against the lateral wall of the distal femoral trochlea
Chondromalacia patellae (softening of the hyaline cartilage)
What is the treatment for patellofemoral dysfunction?
Surgery as a last resort - either releasing a tight lateral retinaculum or if there is a relatively lateralized tibial tubercle, a tibial tubercle transfer to aid patellar trackin
Which way does the patella tend to dislocate?